Caption: Genetic fingerprint. Conceptual image of banded DNA sequences or "genetic fingerprints" seen on hands. The sequence of bands represents the base sequence that forms the genetic code for a section of DNA (deoxyribonucleic acid). Genetic fingerprints are produced by breaking up a DNA sample into fragments and separating these fragments in an electric field (electrophoresis). An autoradiogram of the resulting bands of radioactively-tagged DNA is made by placing a radiographic film on the gel. DNA samples can be used to test for paternity or as evidence in certain criminal investigations.